1. The Field of the Invention
The present invention relates to the field of conveyors for moving products and materials between locations in manufacturing, storage and/or shipping facilities and in particular relates to safety devices for conveyors consisting of an overhead track and a wheeled carrier. Even more particularly, the invention relates to a safety switch which permits opening of the track to provide a gap between spaced ends of the track and prevent the movement of the carrier toward the gap and off of the track while the track is open.
2. The State of the Prior Art
Overhead conveyors systems consisting of an overhead track and wheeled carriages which ride on the track for moving products and materials between locations in manufacturing, storage and/or shipping facilities are well known. A problem exists in such systems because the overhead track is sometimes in a position to interfere with other operations. In certain instances, such a track may be in a location where it interferes with the operation of another transversely extending overhead track. In other instances, such as when the load needs to be moved from one level of a facility to another on an elevator, the track might interfere with the proper operation of the elevator.
To eliminate these interferences, it has been known to provide a switch consisting of a short segment of track which is removable at the point where the interference might otherwise occur. Often, the short segment of track is simply swingably mounted on the end of one of the tracks adjacent the gap, and some sort of a support is provided on the track on the opposite side of the gap from the place where the short segment is swingably mounted. To open the track and provide a gap which avoids the undesirable interference, the free end of the short segment may be manually lifted from the support and allowed to swing downwardly into a hanging or depending position. After there is no longer a need for the switch to be open, the free end of the short segment is simply lifted back up and positioned on the support to once again provide a continuous track.
A major problem with an arrangement such as that described above is that a carriage on the free end of the track adjacent the gap might accidently be caused to move toward the gap and fall. This of course is quite dangerous because the loads on the carriages are heavy and falling would create a hazardous situation not only for the load itself but also for objects and persons below.
In accordance with the broadest concepts and principles of the invention, the same provides solutions for and/or relief from the prior art problems discussed above. In particular, the invention provides means for preventing carriages from moving toward a gap in a track when the track is in an open condition. Thus, the invention provides an overhead conveyor track system for a wheeled carrier having at least one wheel adapted for traveling along a track and a depending load bracket. The system includes first and second elongated conveyor tracks having respective free ends. These tracks are adapted and arranged such that the same are in substantial longitudinal alignment with the free ends thereof in spaced relationship presenting a gap therebetween. The system further includes an elongated track segment that is adapted and arranged so as to be placed in the gap in a gap closed position in substantial longitudinal alignment with the tracks. The track segment normally is in the gap in its gap closed position, but is removable from the gap so as to provide the system with a gap open condition. In accordance with the principles and concepts of the invention, the system further comprises an automatic safety switch mechanism which includes at least one moveable track blocking element that is operably coupled with the segment when the latter is in its gap closed position, and which is effective, when the segment is removed from the gap and the system is therefore in its gap open condition, to block at least one of the free ends of the tracks to prevent movement of a carrier toward the gap. Ideally, the automatic safety switch mechanism may include two moveable track blocking elements whereby both of the free ends are blocked when the system is in its gap open condition.
In further accordance with the concepts and principles of the invention, the elongated track segment may have spaced ends, one of which is may be moveably attached to the free end of the first track for movement between a gap closed position and a gap open position. Desirably, the segment may be pivotally attached to the free end of the first track for swinging between its positions about a horizontal axis. In this form of the invention, the safety switch mechanism may be effective when the segment is in its gap open position to block the free end of the second track to prevent movement of a carrier on the second track toward the gap. In one preferred form of the invention, the system may include at least one overhead support assemblage for the second track and at least a portion of the safety switch mechanism may be carried by the support assemblage. Desirably, the support assemblage may be attached to an upper structure of an elevator.
Alternatively, or additionally, the system may include a track blocking member at the end of the segment which is attached to the first track and which is effective when the segment is in its gap open position to block the free end of the first track to prevent movement of a carrier on the first track toward the gap.
In a preferred form of the invention, the safety switch mechanism may be mounted adjacent the free end of the second track and may include a track blocking and unblocking element comprising an elongated arm that is moveable between track blocking and track clearing positions. Desirably, the arm may be operable in its track blocking position to prevent the movement of a carrier on the second track toward the gap. In this form of the invention, the safety switch mechanism may desirably include a latching member that is operably connected to and moves with the arm. The system may further include a latch element operably associated with the track segment and disposed, when the track segment is in its gap closed position, to contact the latching member and thereby prevent movement of the arm to its track blocking position. Ideally, the safety switch mechanism may include a biasing element, that may be in the form of a counterweight or a coil spring that is operably connected to the arm to urge the latter toward its rail blocking position. In one preferred form of the invention, the track blocking and unblocking element may be pivotally mounted for swinging about a horizontal axis to move the arm between its blocking and clearing positions.
Ideally, the safety switch mechanism may include an elongated appendage that is operably connected to the track blocking and unblocking element so that the arm and the appendage move in unison. Desirably, the latching member (portion) is positioned at a free end of the appendage and the same is positioned for contacting the latch element such that the contact between the latch element and the latching portion prevents movement of the elongated appendage and thereby movement of the arm to its track blocking position.
Alternatively, or additionally, the system may include a track blocking member at the end of the segment that is attached to the first track and which includes an extension element located so as to block the free end of the first track when the segment is in its gap open position to prevent movement of a carrier on the first track toward the gap. Desirably, the extension element comprises at least one leg mounted adjacent the end of the track segment so as to swing into a position alongside the first track when the track element swings into its gap open position.
In accordance with the principles and concepts of the invention, the invention provides a composite assemblage of components presenting an overhead conveyor track system for a wheeled carrier having at least one wheel adapted for traveling along a track and a depending load bracket. Desirably, the system may include a first elongated conveyor track having a free end, and a second elongated conveyor track having a free end. The tracks may desirably be adapted for arrangement in substantial longitudinal alignment and with the free ends thereof in spaced relationship presenting a gap therebetween. The overall system includes an elongated track segment having spaced first and second ends and which is adapted for being positioned in the gap in substantial longitudinal alignment with the tracks. Ideally, the first end of the segment is rotatably attached to the free end of the first track for swinging movement between a horizontal gap closed position and a gap open position where the track segment depends vertically from the free end of the first track.
Preferably, the system may include a receptacle mounted at the free end of the second track for releasably supporting the second end of the track segment when the track segment is in its gap closed position and prevent it from swinging downwardly into its gap open position. The system may also preferably include an automatic safety switch mechanism that is mounted adjacent the free end of the second track. The safety switch mechanism desirably includes a track blocking and unblocking element, an elongated rocker element and an elongated pivoting beam structure.
The track blocking and unblocking element may be mounted for rotation about a horizontal axis that extends transversely therethrough, and the same may include an elongated arm that is moveable between track blocking and track clearing positions when the track blocking and unblocking element swings about the horizontal axis. The arm is operable in its track blocking position to prevent movement of a carrier on the second track toward the gap.
The rocker element may desirably have a pair of spaced ends, and the same may be rotatable about a horizontal axis that extends transversely therethrough between the spaced ends thereof and which is essentially perpendicular to the axis of rotation of the track blocking and unblocking element.
The beam structure may also have a pair of spaced ends, and this component also may be mounted so as to pivot about a horizontal axis that extends transversely therethrough between its spaced ends. The pivot axis of the beam structure desirably is essentially parallel to the axis of rotation of the rocker element. Ideally, the beam structure may include a laterally extending appendage that extends toward the second end of the track segment when the track segment is in its gap closed position in essential parallelism relative to the axis of the pivoting beam structure. The appendage desirably has a latching portion at its free end that is disposed in proximity to the second end of the track segment when the track segment is in its gap closed position.
In accordance with the concepts and principles of the invention, the track blocking and unblocking element, the rocker element and the beam structure may desirably be linked together so as to pivot about their respective axes in unison in response to the urging of a counterweight or a spring element that is connected to at least one of the track blocking and unblocking element, the rocker element and the beam structure in a position to urge the arm toward its track blocking position.
In further accordance with the concepts and principles of the invention, the system includes a latch element comprising a latch plate extending laterally from the track segment at a location adjacent the second end thereof. Desirably, the latch element is in a position, when the track segment is in its gap closed position, to contact the latching portion at the free end of the appendage and prevent the appendage and thereby the beam structure, the rocker element, and the track blocking and unblocking element from moving under the influence of the biasing element when the track segment is in its gap closed position. Thus, the arm is prevented from moving to its track blocking position when the latch element and the latching member are engaged.
Finally, in its composite form, the system provides a track blocking member at the first end of the track segment including an extension element located to block the free end of the first track when the segment is in its gap open position to thereby prevent movement of a carrier on the first track toward the gap. Ideally, the track blocking member may comprise a leg mounted at the first end of the track segment which extends outwardly away from the first end in a direction essentially parallel to the track segment so as to swing upwardly into a first track blocking position alongside the first track when the track element swings downwardly into its gap open position.
Preferably, the system includes at least one overhead support assemblage for the first track and at least one overhead support assemblage for the second track, and the safety switch mechanism is desirably carried by the support assemblage for the second track. In one preferred form of the invention, the support assemblage for the second track may be attached to an upper structure of an elevator.